Average acceleration of an astronaut

[Edwardo_Elric]

Homework Statement

An astronaut has left spacelab V to test a new space scooter for possible use in constructing Space Habitat I. Her partner measures the following velocity changes, each taking a place in a 10-s interval. What are the magnitude, the algebraic sign and and the direction of the average acceleration in each interval described below? Assume that the positive direction is to the right.

a.) At the beginning of the interval the astronaut is moving to the right along the x-axis at 20.0m/s, and at the end of the interval she is moving to the right along the x-axis at 5.0 m/s.

b.) At the beginning, she is moving to the left at 5.0m/s and at the end she is moving to the left at 20.0m/s

c.) At the beginning she is moving to the right at 20.0m/s, and at the end she is moving to the left at 20.0m/s

Homework Equations

$$\vec{a}_ave = \frac{\Delta {V}}{\Delta{t}}$$

The Attempt at a Solution

a.) Required A_ave
20m/s to right then 5.0m/s right at end
a_{ave} = (V2-V1)/(10s)
a_{ave} = ( 5.0m/s - 20.0m/s)/(10s)
a_{ave} = -1.5m/s
a is negative the acceleration is to the left


b.) 5.0m/s to left then 20.0m/s left at the end

a_{ave} = (V2-V1)/(10s)
a_{ave} = (-20-(-5.0m/s)/(10s)
a_{ave} = -1.5m/s
a is negative the acceleration is to the left

c.) a_{ave} = (-20.0m/s - (20.0m/s))/ 10s
a_{ave} = (-40m/s)/(10s)
a_{ave} = -4.0m/s^2
acceleration still to the left and motion to the left
...
can u check my answers

 

[andrevdh]

You seem to have got this problem under control. I agree with all of your answers.

 

[Edwardo_Elric]

thanks for checking my work andrevdh